The fire was reported about 1:10 p.m. north of westbound Highway 126 at Briggs Road. The winds carried embers to the other side of the freeway and the center divider, causing spot fires and threatening agricultural buildings in the area.

The fire, fanned by Santa Ana winds, burned about 30 acres along the highway, leaving scores of motorists stuck in their vehicles.

Authorities had to close a lane in each direction as firefighters battled the blaze throughout the afternoon.

Mike Lindbery, Ventura County fire spokesman, said those lanes would likely stay closed because the fire had burned wooden posts that are part of the highway's center divide. Caltrans workers were expected to remain on scene throughout the night and into early Thursday fixing the damage, he said.

The blaze was originally a 100-by-200-foot spot fire near eucalyptus trees on a ramp of the highway. It soon was burning grass and oleander, officials said.

The California Highway Patrol shut the highway between Peck and Wells roads during the blaze, causing a backup. Firefighters got a handle on the blaze north of the freeway but needed it clear to work on the south side and the center divider, officials said. Some power lines that fell on the freeway also needed to be cleared.

CHP officers diverted traffic by having drivers make a U-turn and head west on the eastbound side until a break in the roadway, where they continued in the right direction, Officer Steve Reid said.

The Ventura County Sheriff's Office said one lane in each direction between Wells and Briggs roads were opened just after 4 p.m.

Smoke was heavy on the highway as the fire was burning, creating tough working conditions in the agricultural area, officials said.

Nearby Briggs School let students go home early, and parents were advised to pick up their children in front of the campus.

Ventura and Santa Paula city fire departments assisted in the incident, along with the California Department of Forestry and Fire Protection.

No structural damage or injuries were reported, although some irrigation lines apparently burned. The fire burned near greenhouses.

Officials were expected to release more information on the fire Thursday.

Wednesday had been forecast as one of the hottest days of the week.

Camarillo and Ojai reached 97, while Oxnard and Ventura got up to 96 degrees, according to the National Weather Service.

High temperatures were also expected Thursday.

Cooler weather was expected by Friday, with temperatures back to normal by Sunday, forecasters said.

During the heat wave, the weather service recommends residents drink plenty of nonalcoholic fluids, dress in lightweight clothing and never leave a child, elderly person or pet in a vehicle, even for a short time.

Staff writers Teresa Rochester and John Scheibe contributed to this report.